Install Aria2 and webui on Raspberry Pi with one simple script.

RPi-aria2-with-webui.sh

#!/bin/sh

DOWNLOAD_DIR="${HOME}/MiniDLNA"
CONFIG_DIR="${HOME}/.aria2"
RPC_TOKEN="changeIt"
RPC_PORT="6800"

change_apt_source(){
	if [ -f /etc/apt/sources.list ]; then
		sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak
	fi
	sudo sed -i '/^deb.*/s/^/# /g' /etc/apt/sources.list
	sudo chmod 666 /etc/apt/sources.list
	sudo echo "deb http://mirrors.tuna.tsinghua.edu.cn/raspbian/raspbian/ jessie main non-free contrib" >> /etc/apt/sources.list
	sudo echo "deb-src http://mirrors.tuna.tsinghua.edu.cn/raspbian/raspbian/ jessie main non-free contrib" >> /etc/apt/sources.list
	sudo chmod 644 /etc/apt/sources.list

}
# change_apt_source

sudo apt-get update
sudo apt-get install -y aria2 ca-certificates

if [ ! -d ${DOWNLOAD_DIR} ]; then
    mkdir -p ${DOWNLOAD_DIR}
fi

if [ ! -d ${CONFIG_DIR} ]; then
    mkdir -p ${CONFIG_DIR}
fi

if [ ! -f ${CONFIG_DIR}/aria2.session ]; then
	touch ${CONFIG_DIR}/aria2.session
fi
if [ ! -f ${CONFIG_DIR}/aria2.log ]; then
	touch ${CONFIG_DIR}/aria2.log
fi

if [ -f ${CONFIG_DIR}/aria2.conf ];then
	mv ${CONFIG_DIR}/aria2.conf ${CONFIG_DIR}/aria2.conf.bak
fi

# Generate cfg file
cat > ${CONFIG_DIR}/aria2.conf <<-EOCFG
# For full reference:
# https://aria2.github.io/manual/en/html/aria2c.html
##
dir=${DOWNLOAD_DIR}
file-allocation=trunc
continue=true
# daemon=true
##
log=${CONFIG_DIR}/aria2.log
console-log-level=warn
log-level=notice
##
max-concurrent-downloads=5
max-connection-per-server=10
min-split-size=5M
split=10
disable-ipv6=true
##
input-file=${CONFIG_DIR}/aria2.session
save-session=${CONFIG_DIR}/aria2.session
save-session-interval=30
##
enable-rpc=true
rpc-allow-origin-all=true
rpc-listen-all=true
rpc-listen-port=${RPC_PORT}
rpc-secret=${RPC_TOKEN}
##
follow-torrent=mem
follow-metalink=mem
enable-dht6=false
peer-id-prefix=-TR2770-
user-agent=Transmission/2.77
seed-time=0
#seed-ratio=1.0
bt-seed-unverified=true
bt-save-metadata=true
EOCFG


# MiniDLNA
sudo apt-get install -y minidlna
sudo cp /etc/minidlna.conf /etc/minidlna.conf.origin
sudo sed -i 's#^media_dir=/.*#media_dir='${DOWNLOAD_DIR}'#g' /etc/minidlna.conf
sudo sed -i '/#inotify=yes/s/#//g' minidlna.conf #Enable media auto discover
sudo sed -i '$a fs.inotify.max_user_watches=65536' /etc/sysctl.conf


# aria2-webui on lighttpd
sudo apt-get install -y lighttpd unzip
wget https://github.com/ziahamza/webui-aria2/archive/master.zip
unzip -qu master.zip
cd webui-aria2-master/
change_token(){
	sed -i '/token:/s/\/\///g' configuration.js
	sed -i 's/\$YOUR_SECRET_TOKEN\$/'${RPC_TOKEN}'/g' configuration.js
}

# change_token

sudo cp -Rfu . /var/www/html/
cd ..
rm -rf webui-aria2-master master.zip

echo "Done!"
echo "Your Aria2 configuration and log file are in : ${CONFIG_DIR}"
echo "Your RPC token is: ${RPC_TOKEN}"
echo "Start aria2 with 'aria2c -D' and enjoy!"

after finish message in order to start webui service use this commands
sudo openssl rand -base64 32
it will give you a long key
copy it and use it in this command
aria2c --enable-rpc --rpc-listen-all --rpc-secret="paste here your key and delete quotes" --daemon
after that you can login into webui by typing your raspberry lan ip (192.168.xxx.xxx)
after that in order to use webui open Settings-->Connection Settings
paste your key into "Enter the secret token (optional):" area and hit Save Connection configuration.